Chimp & See Talk

Habitat Fragmentation and Chimpanzees

  • MimiA by MimiA scientist, moderator

    Hi everyone, I know a lot of you are interested in the science side of the work we do so I thought I would post an article by Maureen McCarthy who is a moderator here (user name @maureenmccarthy). In the piece she talks about our latest paper on chimpanzees and habitat fragmentation in Uganda (and what we can learn by studying them non invasively using genetics)

    http://blogs.biomedcentral.com/bmcseriesblog/2015/08/25/seeing-forest-trees/

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  • AnLand by AnLand moderator in response to MimiA's comment.

    Thanks for the link to the blog text and the paper. I will now have forever in my mind the vision of Gertrude teaching Cali and Jax how to safely cross a highway. 😉

    But more seriously, I don't really understand the notion of the Y haplotypes. I know what it is basically, but does it mean that there is only one Y haplotype within one community or is each haplotype (or most of them) only found within one community. Means: how many Y haplotypes are (on average) found in each community. And - if it is only one (that - what I understand from the paper - would be expected): what does it mean in respect to the separateness (or age) of the community? It would take a while to develop distinctive haplotypes, or? And the communities are quite small. Or do I misunderstand this? I don't know whether I can make myself here clear: how long must a community exist to have one and only one distinctive Y haplotype - and this in relation to these small groups and fragmented environment. (If I get it right, the paper discusses only why more than one haplotype might be present, I think.)

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  • MimiA by MimiA scientist, moderator

    HI @AnLand

    That's a lot of questions! 😄

    A good starting point is here: http://ngogochimpanzeeproject.org/wordpress/wp-content/uploads/2014/04/Langergraber-et-al.-2014-JHE.pdf

    In Maureen's study, some groups have more than one Y haplotype and some have just one, and some haplotypes are shared between communities. So there aren't any easy answers to your questions.

    Also note that in this study, we aren't sure we have all the males for each group, in fact based on the population estimate we know we don't, so there may be more diversity that what is observed.

    Having 1 haplotype is what you expect in a newer group or in a group with heavy mating skew and small overall size. The size of groups can also change over time and go through bottlenecks of diveristy.

    other work you may find of interest:

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  • AnLand by AnLand moderator

    Hi @MimiA,

    thanks a lot. The first paper by Kevin Langergraber is a great reading with lots of (for me) new ideas. I have to admit that it is not easy for me to think of a chimp community in such a long time frame - especially with the implications at the end of the paper that probably not the immigrant is the "innovator", but culture is based in the group and might be as old as the group or even a founding factor of the community (that's maybe a bold interpretation of what is actually claimed in the paper). I need to go through the other papers later. Just briefly, can you statistically infer how many haplotypes you are probably missing (in Maureen's study) or is it too complicated with this small communities? Sorry, too many new questions. I should probably read the other papers first.

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  • MimiA by MimiA scientist, moderator

    hi @AnLand, even if the groups were big we wouldn't be able to infer the missing haplotypes, it really isn't a clear pattern across groups, forests or even subspecies!

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  • MimiA by MimiA scientist, moderator

    Hi again

    I forgot to link to my own paper! http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0014761

    In this work, we defined groups based on clustering of haplotypes and we infer from the low haplotype diversity that the groups are all relatively recent and we suspect recent colonization/expansion into the Loango habitat. You can see from the work of Schubert and Lukas though (links above) this is different from what we see at Tai and somewhat different from what is seen at Ngogo (Langegraber paper).

    Also important to note is that it could be the markers we use happen to be less diverse in central chimps even though their overall diversity is not lower (this is called ascertainment bias, we don't expect it to really be the case since the markers were developed in human and then bonobos, but it could be)

    finally @AnLand was PMing me about group size so I will reply here too: Chimp groups range quite a bit in size, a healthy chimp group can be 20 individuals or more and we don't think the groups Maureen studies are necessarily that small, certainly not on the large end, but they don't seem tragically small by any account.

    and one more paper on the topic from Ugalla Tanzania (savannah chimps)

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  • AnLand by AnLand moderator in response to MimiA's comment.

    Thanks! Need to read now. 😉

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  • maureenmccarthy by maureenmccarthy scientist, moderator

    Thanks, AnLand and MimiA! Great discussion! I would only add one point to hopefully help clarify the Y haplotype questions you brought up, AnLand. In the new paper, we discuss why a single haplotype might be present across multiple putative communities. If we assume that Y haplotypes are highly reliable markers of community affiliation, this might lead us to conclude that two putative communities sharing the same Y haplotype are in fact one community instead but that we failed to sample individuals together in such a way that would link them spatially. We argue, however, that this is likely not that case. First, we know that Y haplotypes are not perfect and 100% reliable markers of community affiliation, but we do see a loose relationship even in this study population. Where there are haplotypes shared among multiple communities, this could be for a number of reasons we list, including for example male copulations with females in other communities (among other possibilities).

    As for how many haplotypes we would expect, Mimi did a great job of explaining that this isn't straightforward and is influenced by things like community age and reproductive skew. So it's a bit complicated but there are definitely some cool papers like the ones Mimi recommended that discuss these issues further.

    Thanks for your interest and for the great conversation! 😃

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  • AnLand by AnLand moderator in response to maureenmccarthy's comment.

    Thanks, @maureenmccarthy! Yes, I misunderstood that part of your paper assuming that this means at the same time that you expect one - and only one - Y haplotype within one community. I see that this is not the case or only in the cases that MimiA mentioned above (newer community and skewed mating). You were more surprised(?) that the same haplotype has been found in more than one community questioning the separateness of the communities. But I need to go a bit deeper into the papers to really understand how the male philopatry and female dispersal of chimps can be seen at the DNA level. But definitely interesting.

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  • Snorticus by Snorticus in response to MimiA's comment.

    @MimiA, referring to your paper, can you talk about possible reasons why male chimp C79 was found associating with 3 different groups?

    "Finally, haplotype C male C79 was initially found in the center of the haplotype C MCP then in the northeastern limit of group BI's MCP and then, as described above with a haplotype A male (C136). Chimpanzee males have rarely been observed to transfer between groups even in the case of group dissolution [36], [59], [60], making the tracking of this male highly intriguing."

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  • MimiA by MimiA scientist, moderator in response to Snorticus's comment.

    Hi @Snorticus

    The 2 most likely possibilties:

    • all my territory boundaries are minimum boundaries and we know chimp territories overlap, so maybe in all instances he still is in his territory. In the final association with C136 this may be that the A group was once again agressing group C having both males at the same place at the same time.

    • maybe he successfully transfered to group A either as an adult (unlikely) or as a juvenile associated with a mom that transferred, when he is the BI area that could very well be an area of territory overlap of A and BI that we just didn't pick up with our sampling

    Here is our paper on the dissolution of the group (when it first started happening) http://www.mimiarandjelovic.com/uploads/2/7/4/5/27456225/fatal_chimpanzee_attack_ijp_2007.pdf

    😃

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  • Snorticus by Snorticus in response to MimiA's comment.

    Wow, that was a gripping read! So are you thinking that A group probably just opportunistically murdered this male as a member of the C group, or did they actually target this particular C male individual? It requires such a high level of thought to have planned, organized, and carried out this whole murder scenario, how fascinating. Any update papers on group C? When you add murder to haplotypes you pique my interest. 😉

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  • MimiA by MimiA scientist, moderator in response to Snorticus's comment.

    We don't have any new papers on the dissolution of group C but the field reports lean towards this group being gone now. What we know from other chimp group extinctions at other sites is that usually some of the females are then integrated into new groups (others may be killed) and the males are genrally killed off as far as we know. I don't think it is know if specific males are targeted but I would guess it is not so, and rather it is opprtunistic during boundary patrols and incursions (the males/indivduals that are present near borders are slowly picked off).

    Here is a classic video of an Ngogo group going on an incursion (raid): https://www.youtube.com/watch?v=a7XuXi3mqYM
    In this video they eat the infant they catch though generally when they kill a rival male they do not canibalize it which is how we usually know a male has been killes in an intercommunity attack rather than by a predator.

    There was a great paper out in 2010 on this hapenning in Ngogo, Kibale, Uganda:
    http://ngogochimpanzeeproject.org/wordpress/wp-content/uploads/2012/07/Mitani-et-al.-2010-CB.pdf

    http://news.sciencemag.org/social-sciences/2010/06/chimpanzees-kill-land

    wikipedia also has an entry on this happening at Gombe, Tanzania:
    https://en.wikipedia.org/wiki/Gombe_Chimpanzee_War

    here is some more: https://www.newscientist.com/article/mg22229682-600-only-known-chimp-war-reveals-how-societies-splinter/

    and there are also several papers on this from Mahale, Tanzania:
    http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0310.1985.tb01395.x/abstract

    other reading:
    http://www.eva.mpg.de/primat/staff/catherine_crockford/pdf/Boesch&al(2008)AJP70(6).pdf

    http://www.unl.edu/rhames/courses/war/wrang-an-rev-violence.pdf

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  • Snorticus by Snorticus

    That was engrossing and brutal Sunday reading. Have you found this raiding and cannibalizing behavior in every chimp community that has been studied including the communities we are viewing on chimpandsee?

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  • MimiA by MimiA scientist, moderator in response to Snorticus's comment.

    Hmmm, I am not entirely sure but here is a good read too: http://blogs.scientificamerican.com/cross-check/chimp-violence-researchers-respond-to-criticism-on-cross-check/

    In it, it states: "Evidence for lethal aggression has been found in seven of the of eight never-provisioned study sites (Budongo, Fongoli, Goualougo, Kalinzu, Kibale, Kyambura, Taï); the only exception is the small, isolated population at Bossou."

    But again, the raiding is usually not accompanied by cannibalization as far as i know, for sure there are lethal encounters but eating adults is not considered common. Cannibalization, when it happens, is usually infants and can be within or between groups and it is very poorly understood and rare (again, to the best of my knowledge).

    and just to note, bonobos seem to do it too: https://www.newscientist.com/article/dn18454-hippy-apes-caught-cannibalising-their-young/

    Almost all of the chimp&see sites are not long term sites and the chimps are unhabituated, so as far as i know it hasn't been reported for any of these communities we have on our videos. For one site that is just wrapping up now, we have evidence for it from a bloody and diarrhea-filled scene our site manager happened upon which we think was an intergroup encounter, very similar to what we reported on from Loango in 2007. Once it is uploaded I'll let you know which one 😉

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  • Snorticus by Snorticus

    I should have phrased that question better. I meant to use the two things - raids; cannibalism; as separate examples of violent chimp behavior and not necessarily concurrent - although it just occurred to me that cannibalism can be opportunistic and not necessarily violent if the victim wasn't killed by the consumer.

    I was surprised to read this in your Wilson & Wrangham link where one section discusses pre-2003 infanticides:

    http://www.unl.edu/rhames/courses/war/wrang-an-rev-violence.pdf
    "Although discussions of lethal intergroup aggression often focus on conflict between adults (e.g., Gat 1999, Sussman 1999), intergroup attacks have resulted in a comparable number of infant victims. For example, compared to the 14 or more killings of adults (Table 1), 15 infants are known or inferred to be victims of intergroup attack (Table 2). In addition to intergroup infanticide, a similar number of intragroup infanticides have been reported [N = 12 in which the mother was known to be a stranger and 3 in which the mother’s community was uncertain (Table 6 in Arcadi & Wrangham 1999)]." and the paper discusses the cannibalism of some of the infants post kill.

    Your link https://www.newscientist.com/article/dn18454-hippy-apes-caught-cannibalising-their-young/ somewhat anticipated my next question: Have you found evidence of violence among bonobos in the wild? In this instance it seems like an opportunistic consumption of available protein and not violence to me. Do Bonobo squabbles ever result in injury rather than sex?

    In my non-scientist opinion it seems logical given the evidence cited, that chimp violence is the result of evolution favoring aggression as a strategy, as Michael L. Wilson argues in your link. http://blogs.scientificamerican.com/cross-check/chimp-violence-researchers-respond-to-criticism-on-cross-check/

    Yes please, let me know when the "scene of the crime" is uploaded so I can have a look at it. 😃

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  • MimiA by MimiA scientist, moderator in response to Snorticus's comment.

    For sure bonobos fight, they can be pretty nasty to the males quite often in fact. eg: http://www.jstor.org/stable/4536099?seq=1#page_scan_tab_contents

    and just to be clear - we have no video of the crime. It is just that at that site there was the evidence I reported and you had been asking if we knew of any of the chimp&see sites where there was lethal agression...there is something cool in that video set though,and much much nicer to see.. #nospoilers

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  • Snorticus by Snorticus

    I look forward to seeing the video set, whatever it contains - thanks for no spoilers too!

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  • ksigler by ksigler moderator in response to Snorticus's comment.

    What a dark turn this thread, took! Interesting, though!

    Lol The anticipation builds now as we wait for the bloody and diarrhea-filled post-cannibalism evidence. And whatever the much nicer surprise is. 😄

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  • Snorticus by Snorticus in response to ksigler's comment.

    I know! I hadn't seen this aspect of their behavior discussed much here and @MimiA's initial link to her paper got me really interested in reading more about that side of things. All her links above are really engrossing if you have the time to read them, though as you say - dark stuff - still it's a part of the whole chimp package.

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  • MimiA by MimiA scientist, moderator in response to ksigler's comment.

    sorry, i meant to see we have no video of crime nor crime scene, none of that was on camera traps...and there was no evidence of canabalism, just an intergroup encounter that seemed violent.

    glad you found it interesting! we are always happy to share what we know (and what we don't!)

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  • ksigler by ksigler moderator in response to MimiA's comment.

    I'm okay with that, too. 😃

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  • MimiA by MimiA scientist, moderator

    moved from Chat 😃

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  • AnLand by AnLand moderator

    I made a bit fun of the thought of chimps safely crossing a road and found today a video from the Bulindi Chimp project showing exactly this: "Is the coast clear?" https://www.youtube.com/watch?v=MW1SBbPNS5w (video from October 2012)

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  • drobinso by drobinso

    Funny video!

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  • MimiA by MimiA scientist, moderator

    Sadly that road is a major issue for those Bulindi chimps 😦 https://www.facebook.com/bulindichimpanzees/photos/a.879854938726284.1073741832.833614820016963/1020234998021610/?type=3&permPage=1

    (There is also a chimp at Bulindi named after MAureen: https://www.facebook.com/bulindichimpanzees/photos/a.879854938726284.1073741832.833614820016963/1036473823064394/?type=3&permPage=1)

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  • AnLand by AnLand moderator in response to MimiA's comment.

    Yes, I can imagine. When reading Maureen's paper, I did not picture it as so real, I have to admit. It must be hugely irritating for the chimps to experience these new kind of dangers as traffic. (The loud words when the male chimp stops and turns, do you think they deliberately hurried him and the female over the road?)

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  • Snorticus by Snorticus in response to MimiA's comment.

    I wonder if they would learn to cross over above the road if a jungle-landscaped "bridge" was built for them? Or something like the big logs we have seen them consistently use to cross water? It would probably be too human-smelly for them to trust if humans created one though. I imagine they cross in many areas too.

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  • MimiA by MimiA scientist, moderator

    Hey guys - I just saw that you guys had some follow up! Feel free to PM if I don't reply in the future - it means I just missed it 😃

    @AnLAnd - I am not sure, but it is VERY possible

    @Snorticus - the types of bridges you talk about work well for monkeys so it might work, they may learn its safe. Because of human wildlife conflict issues it may be hard to get people to accept it but its not a bad idea at all 😃

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  • AnLand by AnLand moderator

    There is a follow-up paper to the discussion of the consequences of habitat fragmentation, now looking whether despite the forest fragmentation due to humans there is still evidence that female dispersal (adolescent females migrating to a new community from their natal group) happens. Short answer: yes, there is.

    The first paper had identified several chimp groups in a fragmented area between two major continuous forests. They now wanted to know whether this is a “corridor” that still enables dispersal (migration) from one group to another and to the bigger forests.

    So, what @maureenmccarthy and colleagues did is using the genetic material of the chimps in fecal samples they collected to assign relationships between the chimps and figure out whether mother-daughter and father-son pairs live in the same community or not. You would expect that a mother and her adult daughter don’t live in the same community, if dispersal is true and possible. But you would assume that the male offspring and his father (as well as his mother) live in the same group.

    They found 67 mother-daughter pairs and 26 of some them were found (the samples) in what they had established before as different communities (territories). That’s almost 40%*. In contrast, only 10% of the father-son pairs (5 of 48) showed this and the scientists think that these assignments might not be correct as male dispersal in chimpanzees is virtually unknown.

    These separated “pairs” lived in different communities within the corridor and also in one of the bordering forests, so, yes, there seems to be a corridor, i.e., the fragmented landscape is still enabling the migration between groups. Pretty cool.

    *You may ask why only 40%. First, not all female adolescents leave their community. Second, fecal samples usually don’t tell anything about the age of the one who left it, except maybe for infants. So, other analyzed pairs might live in the same community because the daughter is still too young to disperse. Interestingly, they can show that one female dispersed during the course of the study as her samples was found in a different community 19 months after the collection of the first sample.

    Original paper (paywalled): Maureen S. McCarthy, Jack D. Lester, Kevin E. Langergraber, Craig B. Stanford, Linda Vigilant: “Genetic analysis suggests dispersal among chimpanzees in a fragmented forest landscape in Uganda” https://onlinelibrary.wiley.com/doi/abs/10.1002/ajp.22902

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